[求助]新手求助~（关于初级的神经网络问题） [复制链接]

各位大虾，我在网上看到的教程里的一个程序段，本来想要试试看的： ?v>ET2wD  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); sVG(N.y  
net.trainParam.show = 50; /|6;Z}2  
net.trainParam.lr = 0.05; 3gd&i  
net.trainParam.epochs = 300; J{^RkGF  
net.trainParam.goal = 1e-5; GFr|E
8  
p = [-1 -1 2 2;0 5 0 5]; S26MDLk`R3  
t = [-1 -1 1 1]; s(X;Eha  
net=train(net,p,t); P ;IrBq6|o  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 Reatdh  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 V<k8N^  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 q.,JVGMS  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 `{qG1  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 @v}/zS  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 mZd , 9  
TRAINGD, Performance goal met. sc,Xw:YO  
a = sim(net,p) _h}kp\sps  
plot(p,t,p,a,'o') M|:UwqV>  
但是为什么老是报错： |4'Y/re  
??? Input argument "net" is undefined. E Cyyl